138 



AX AMERICAN GEOLOGICAL RAILWAY GUIDE. (ILL.) 



63. Fine outcrops of Keokuk limestone with numerous fossils, and geodes containing crystal - 

 ized quartz, chalcedony, calcite, dolomite, arragpnite, blende and pyrite. 



64. Cincinnati group with characteristic fossils, and near Savanna the Niagara limestone caps the 

 hills and affords silicified corals in abundance. 



